POS1012 PATIENT CHARACTERISTICS AND CLINICAL ASSESSMENTS ASSOCIATED WITH PROGRESSION FROM NON-RADIOGRAPHIC AXIAL SPONDYLOARTHRITIS TO ANKYLOSING SPONDYLITIS
Authors: S. Kieskamp, R. Wilbrink, M. Siderius, F. Wink, R. Bos, H. Bootsma, S. Arends, A. Spoorenberg
Journal: Annals of the Rheumatic Diseases (2022)

Background Part of the patients with non-radiographic spondyloarthritis (nr-axSpA) will progress to ankylosing spondylitis (AS). Varying factors are reported to be predictive of this progression of which the presence of elevated CRP and active sacroliitis on MRI are most often found 1 . Objectives To explore patient characteristics and clinical assessments associated with progression from nr-axSpA to AS up to 6 years follow-up in daily clinical practice. Methods Patients from the ongoing Groningen Leeuwarden axial SpA (GLAS) cohort classified as nr-axSpA enrolled into the cohort (baseline) between 2009 and 2018 were included in the analyses. Nr-axSpA was defined as sacroiliitis of ≥ 2 grade bilaterally or ≥ 3 unilaterally on the AP view of pelvic radiographs, according to the modified New-York (mNY) criteria. Baseline and available radiographs at 2 (n=85), 4 (n=53) and 6 years (n=30) of follow-up were randomized with radiographs of patients with AS and scored with known time sequence according to the mNY criteria by 2 trained readers (SK and RW). In case of disagreement in classification, the score of a third independent reader (AS) was used. Progression to AS was defined as progression in mNY sacroiliitis score to a score of ≥2 bilaterally or ≥3 unilaterally at any time during the 6-year follow-up period. Patient characteristics and clinical assessments at baseline were compared between patients who did and did not progress from nr-axSpA to AS, using chi-squared tests, Mann-whitney U tests or independent t-tests when appropriate. Results 85 patients were classified as nr-axSpA at baseline. Mean age was 39±11 years, 52% was male, median symptom duration was 6 (IQR 3-17) years, 75% was HLA-B27 + , and mean ASDAS was 2.7±1.1. After 2, 4 and 6 years, 9/85 (10.6%), 4/47 (8.5%) and 2/24 (8.3%) of nr-axSpA patients progressed to AS. In total, 15 patients progressed to AS and 31 and 19 patients did not yet reach follow-up at 4 and 6 years, respectively. Patients with nr-axSpA progressing to AS were significantly more often current smokers (62% vs. 21%, p=0.003) and had more often a history of uveitis (47 vs. 11%, p=0.001). Furthermore, patients with nr-axSpA progressing to AS tended to have higher CRP (and therefore ASDAS), more entheseal involvement, and worse lumbar spinal mobility then non-progressors; however, due to the relatively low number of progressors during the analyzed follow-up period, significance could not be reached (Table 1). Table 1. Comparison of baseline characteristics between patients with nr-axSpA who did and did not progress to AS. Values presented as mean ± SD, median (IQR) and n (%) for normally distributed, non-normally distributed and categorical variables, respectively. *p&lt;0.05. Baseline characteristics All patients (n=85) No progression (n=70) Progression (n=15) p Male sex 44 (52%) 39 (56%) 5 (33%) 0.115 Age 38.6 ± 10.8 38.4 ± 10.2 39.5 ± 13.8 0.774 Symptom duration 6 (3 – 17) 7 (3 – 16) 4 (2 – 20) 0.663 HLA-B27 + 62 (75%) 52 (74%) 10 (67%) 0.758 Currently smoking 22 (28%) 14 (21%) 8 (53%) 0.003* BMI 26.1 ± 4.4 26.2 ± 4.5 25.8 ± 4.2 0.750 History of uveitis 15 (18%) 8 (11%) 7 (47%) 0.001* History of IBD 7 (8%) 6 (9%) 1 (8%) 0.808 History of psoriasis 12 (14%) 10 (15%) 2 (13%) 0.923 ASDAS 2.7 ± 1.1 2.6 ± 1.1 3.2 ± 1.0 0.107 - ASDAS &gt;2.1 51 (72%) 41 (68%) 10 (91%) 0.126 BASDAI 5.3 (3.4 – 6.7) 5.4 (3.2 – 6.8) 4.7 (3.6 – 6.7) 0.538 CRP ≥5.0 21 (27%) 16 (25%) 5 (39%) 0.320 Start TNFi (during first 2 years of follow-up) 27 (32%) 23 (33%) 4 (27%) 0.640 Chest expansion (cm) 5.2 ± 2.1 5.3 ± 2.1 4.7 ± 2.1 0.367 Lateral spinal flexion (cm) 14.4 (10.5 – 17.5) 14.5 (10.7 – 17.7) 11.3 (9.0 – 17.5) 0.163 mSchober (cm) 14.1 ± 1.3 14.1 ± 1.3 13.7 ± 1.3 0.308 Conclusion In our cohort, active smoking and a history of uveitis were independently associated with the progression of nr-axSpA to AS. Combining data of different cohorts will help to assess a more robust picture of axSpA features and patient characteristics associated with progression to AS. References [1]Protopopov M, Poddubnyy D. Expert Rev Clin Immunol. 2018;14(6):525-533 Acknowledgements The GLAS cohort has received unrestricted grants from Novartis. Disclosure of Interests Stan Kieskamp: None declared, Rick Wilbrink: None declared, Mark Siderius: None declared, Freke Wink: None declared, Reinhard Bos: None declared, Hendrika Bootsma Speakers bureau: Bristol-Myers Squibb, Novartis, Consultant of: Bristol-Myers Squibb, Roche, Novartis, Medimmune, Union Chimique Belge, Grant/research support from: Unrestricted grants from Bristol-Myers Squibb and Roche, Suzanne Arends: None declared, Anneke Spoorenberg Paid instructor for: Abbvie, Consultant of: AbbVie, Novartis Pharma, Pfizer, UCB Pharma, Lilly, Grant/research support from: Novartis Pharma, Pfizer